Preheat oven to 400°F (200°C) and line a baking sheet with foil or parchment paper.
Slice the bread in half lengthwise (or into thick slices) and place on the baking sheet.
In a bowl, mix butter, garlic, salt, pepper, Italian seasoning, and parsley until smooth.
Spread the garlic butter evenly over the bread.
Sprinkle mozzarella on top, then add cheddar and parmesan if using.
Bake for 10–12 minutes until the cheese is melted and bubbly.
Broil for 1–2 minutes if desired for a golden top.
Cool for 2 minutes, slice, and serve warm.